The present invention relates to an endoprosthesis for an anatomical canal, which is intended to be implanted inside an anatomical canal, in a region of this canal that is experiencing impairment and of which the exterior surface of the wall bears projecting studs intended to collaborate with the wall of said anatomical canal in order to hold said endoprosthesis in position therein.
Such an impairment may be an affliction, such as a stenosis or a collapsus, leading to narrowing of said anatomical canal and combated, in the known way, using an implanted endoprosthesis when the reduction in the diameter of said canal is significant, for example greater than 50%. This endoprosthesis holds the passage of said canal open at said region, allowing fluids to circulate through it. Such an endoprosthesis acts essentially as a mechanical stent.
It is also known that implanting such an endoprosthesis for holding a passage open is generally associated with suitable medical treatment, such as the administration of anti-inflammatory drugs, of radiotherapy, of chemotherapy, etc. Now, this medical treatment is applied in a general way to the patient, that is to say anally, orally or in a drip in the case of drugs and chemical products and by irradiation through the patient's body in the case of radiotherapy. The result of this is that the doses applied to the patient are very much higher than the doses found at the region where the prosthesis is implanted, which means that one or other of the following situations arises:                either there is a desire for the patient not to be subjected to an excessively strong overall treatment, which means that the doses of the treatment at said implantation region are very much lower than they need to be in order to effectively combat said narrowing;        or there is a desire for the doses at the implantation region to be medically effective, which means that the patient is then subjected to very high generalized doses which may prove detrimental to his health.        
Apart from stenosis and collapsus recalled hereinabove, an anatomical canal may suffer other impairments, such as lesions, infections, inflammations, irritations, hypersensitivities, etc. The latter impairments, which hitherto did not lead to the use of an endoprosthesis, require medical treatment which, as mentioned hereinabove with regard to stenosis and collapsus, is applied in the general manner to the patient, with the same disadvantages.
Hence the object of the present invention is to remedy these disadvantages, whatever the type of impairment to the anatomical canal.